Rotor valves are known for use in applications where a source of fluid must be selectively directed to one of several destinations. Such valves have a rotor that can be rotated about its longitudinal axis in a bore of the valve body. When the rotor is rotated to a closed position, the rotor blocks a fluid flow through the valve. A known challenge with this type of valve is how to establish an effective fluid seal between the mating surfaces of the rotor and the valve body while at the same time avoiding excessive operating torque.
U.S. Pat. No. 6,308,739 describes a rotor valve that utilizes a flexible valve seal. This valve is described as being useful for applications such as air conditioning/heating units wherein the heating and cooling flows of the heat pump need to be reversed from time to time. Such applications require the valve to direct fluid from the valve interior to the proper valve body outlet opening, and further to prevent fluid from exiting any other valve body outlet opening. The seal for such a valve may be called an interior pressure seal.
The assignee of the present invention, General Electric Company, produces railway locomotives and off-road vehicles powered by turbocharged diesel engines that utilize a split temperature cooling system, as described in U.S. Pat. Nos. 5,415,147 and 6,230,668, both incorporated by reference herein. The cooling system includes an intercooler that is provided with either hot water or cold water for selectively heating or cooling the combustion intake air during the various modes of operation of the locomotive. A rotor valve used in such applications must not only prevent fluid from exiting the valve body through a closed outlet opening (interior pressure), but in certain operating modes, it must also prevent pressurized fluid from entering the valve body through a closed outlet opening (exterior pressure). One such valve is described in U.S. Pat. No. 6,647,934 that is incorporated by reference herein. The valve seal described in U.S. Pat. No. 6,308,739 has been found to be inadequate for the turbocharged diesel engine cooling system application.